macro_tools 0.85.0

Tools for writing procedural macroses.
Documentation 
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//! This example demonstrates the use of `typ ::type_parameters` from the `macro_tools` crate.
//!
//! ### Example: Trivial One
//!
//! The purpose of `typ ::type_parameters` is to extract type parameters from a given Rust type.
//! In this example, we generate a type `core ::option ::Option< i8, i16, i32, i64 >` and extract its type parameters.
//!

#[ cfg(not(all(feature = "enabled", feature = "typ"))) ]
fn main() {}
#[ cfg(all(feature = "enabled", feature = "typ")) ]
fn main() 
{
  // Import necessary macros and modules from the `macro_tools` crate.
  use macro_tools :: { typ, qt };

  // Generate a token stream representing the type `core ::option ::Option< i8, i16, i32, i64 >`.
  let code = qt!( core ::option ::Option< i8, i16, i32, i64 > );

  // Parse the generated token stream into a `syn ::Type` object.
  // `syn ::Type` is a syntax tree node representing a Rust type.
  let tree_type = syn ::parse2 :: < syn ::Type >(code).unwrap();

  // Extract type parameters from the parsed type.
  // `typ ::type_parameters` takes a reference to a `syn ::Type` and a range.
  // It returns a vector of type parameters within the specified range.
  // Here, `0..=2` specifies that we are interested in the first three type parameters.
  let got = typ ::type_parameters(&tree_type, 0..=2);

  // Iterate over the extracted type parameters and print each one.
  // The `qt!` macro is used to convert the type parameter back to a token stream for printing.
  for e in &got 
  {
  println!("{}", qt!( #e ));
 }

  /* Expected output :
  i8
  i16
  i32
  */
}